<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
        <meta http-equiv="X-UA-Compatible" content="ie=edge" />
        <title>01.字符串的比较</title>
        <script>
            // true 字符串之间是通过编码来比较的
            // alert( 'a' < 'b' );

            var str = '888';

            if ( str >= '0' && str <= '9' ) {
                alert('是数字类型的字符串');
            } else {
                alert('不是数字类型的字符串');
            }
        </script>
    </head>
    <body>

    </body>
</html>
